Despite Mr Tattieheid's plea for the Islay malt to be from one of the Kildalton distilleries (Laphroaig, Lagavulin, Ardbeg), I suspect these three might be harder to find in Byron Bay. If you have a Woolworths chain store near you (i.e. First Estate, BWS, Dan Murphy's, etc) then you'll probably be able to find a bottle of Bowmore Legend. This should do you nicely as a representative whisky from Islay.
When I first read your post, I presumed you were going to look at six different scotches, but I gather from the rest of the replies that other whisky styles are also being considered.
If you're keen for an Irish whiskey, may I suggest you get Black Bush, instead of Bushmills. The Black Bush is a vastly superior whiskey, and I don't think too many people here would disagree. Black Bush is also probably easier to find around Byron Bay, too.
The Balvenie 10yo is a good choice, if you can find it. My advice would be to avoid something like Glenfiddich.....I doubt it will excite too many tastebuds, and it will just make the other whiskies taste better than they really are!
Let me know which liquor store chains you have near you, and I'll then have a better idea of what's available to you.
Alternatively, if you're happy to pay $12 postage (for about 5 bottles), you can get an enormous range of whiskies shipped to you from a special whisky store in Adelaide - they stock a tonne of stuff that isn't normally imported into Oz.